Hoping to speed up your chances for promotion in an age of staff drawdowns and plummeting selection rates? Bone up on your intelligence skills or anatomy books.

An analysis of six years of promotion data conducted by Air Force Times shows that enlisted airmen in intelligence or medical careers who were selected for promotion consistently had some of the lowest average times-in-grade in the Air Force.

For example, airmen in the geospatial intelligence targeteer Air Force Specialty Code who were promoted to master sergeant in 2012 had an average time-in-grade of 3.28 years. That was the fourth-lowest E-7 average time-in-grade that year, and far below the average E-7 time-in-grade of 4.43.

Or take cardiopulmonary laboratory airmen. Those airmen who got promoted to technical sergeant in June had an average time-in-grade of 4.04 years — the second-lowest E-6 time-in-grade this year, and nearly a full year-and-a-half below the overall average of 5.52 years. And surgical service airmen specializing in the musculoskeletal system got promoted to staff sergeant this year after 1.38 years on average. That’s the fourth-lowest E-5 time-in-grade this year, and below the overall E-5 average of 1.98 years.

And some experts say those consistently low times-in-grade could point to a path for eager enlisted airmen to advance in their careers — if they’re willing to be retrained into a challenging and in-demand new job.

“If part of their goal is to advance as rapidly as possible, it’s a very smart decision,” said retired Gen. Billy Boles. “Particularly for those who are blocked from re-enlisting, like security forces, because of overmanning. If you want to stay in the Air Force, you don’t have much of a choice, so that’s a very smart move.”

Getting promoted these days is getting tougher and tougher. Selection rates for staff sergeant and technical sergeant this year fell to their lowest levels since the late 1990s, and master sergeant promotion rates fell to their lowest level in more than a decade. At the same time, the Air Force is offering early retirements and taking other force management steps to draw down its ranks as it faces steep budget shortages.

Boles said he was not surprised to hear that intelligence and medical career fields tended to yield the fastest promotions. The wars in Iraq and Afghanistan created a nearly insatiable need for airmen who can gather and analyze intelligence, and help operate the Air Force’s growing fleet of remotely piloted aircraft.

And medical career fields such as surgical service specialists — who support surgeons by sterilizing tools, administering anesthesia, and providing other assistance — are always valuable. But as thousands of wounded combat veterans recover from more than a decade of war, those career fields are going to be even more in demand.

It’s not just the Air Force that needs those skills, as well as others such as contracting specialists. The civilian world pays handsomely for employees with experience in those fields, said retired Col. Terry Stevens, an Air Force personnel expert, and that demand is creating a retention and turnover problem for the Air Force.

“The opportunities out there are great,” Stevens said. “When you’ve got high turnover at various levels in a career field, you’re going to have more rapid promotion opportunities, because the vacancies are there.”

That’s one reason the Air Force is offering hefty re-enlistment bonuses to airborne cryptologic language analysts, airborne intelligence, surveillance and reconnaissance operators, geospatial intelligence airmen, RPA sensor operators, cardiopulmonary laboratory airmen and contracting officers. And that can mean a huge chunk of change. Staff sergeants with five years of service who are sensor operators and cryptologic language anaylyts, for example, were eligible for bonuses of about $63,000 for re-enlisting for four years in 2013.

And all but four career fields identified by Air Force Times as having some of the lowest times-in-grade were on a list of undermanned career fields released by the Air Force in June. The Air Force hopes airmen will retrain into those undermanned career fields as part of the fiscal 2014 Noncommissioned Officer Retraining Program, or NCORP.

But switching to a new career field may not be for everybody, experts cautioned.

Learning an entirely new skill set inevitably takes time — and the career fields with the fastest promotion rates are often extremely challenging and require months of training. That means that if you’re not planning on making a career out of the Air Force, or are already well into your career, you may not have enough time to catch up to people who have been doing your new job all along.

“There’s a learning curve,” Boles said. “You had credibility when you were a crew chief, but now you’ve got to start all over again on building cred in geospatial intelligence, and a lot of people will say, ‘He’s a newbie.’ It’s easier to retrain at the end of your first enlistment, at age 21 or 25, than when you’re 30 or 35 with 8 or 12 years of service.”

Stevens said airmen who switch careers get a specialty knowledge test waiver for about a year or so, while they get up to speed.

And an airman who switches will likely find himself, at first, in unfamiliar territory and possibly without the friends he’s made over the past few years.

“We all build a comfort zone, and have the bubble of friends,” Boles said. “You’ve got to learn a new language, new rules, become proficient, and you’ve got to be willing to change. You don’t have that network of associates to call and say, ‘Hey, I just ran into something, how do I do this?’”

But while such a switch carries many risks, an airman who pulls it off could reap considerable rewards, Stevens said. A successful transfer into an in-demand career field — one the airman took the initiative to pursue on his own — will look very good to promotion boards once that airman is up for promotion to senior master sergeant or chief master sergeant, Stevens said. Retraining will also improve an airman’s chances of receiving a special assignment, he said.

“When your record comes up for review, the broader experience base you have, the better candidate it makes you,” Stevens said. “They’ll rate that record a heck of a lot higher than if you were, say, just straight personnel all your life.”

Stevens said he held five different jobs in the roughly 12 years he served as an enlisted airman before receiving his commission — everything from postal to personnel to security police — and that having such a breadth of experience gave him a leg up in his career.

“I always liked a challenge,” Stevens said. “I wanted to do everything I could possibly do.”

And although switching to one of these career fields will, of course, make an airman more attractive to a private-sector employer, Stevens recommended not mentioning that perk when asked why you’re requesting retraining.

“They’d say you’re not doing it for the right reasons” and may not grant your request, Stevens said. The right reason, he said, would be to get into a career field that is critical for the Air Force to accomplish its mission and “stay for the long haul.”

Not everybody agrees that switching career fields could improve someone’s chances for a speedy promotion. Chief Master Sgt. Steve Nichols, the Air Force’s enlisted force policy branch chief, said he tells airmen who ask how to get promoted to “put their nose in a book” and do the best job they can where they currently are.

“It sounds cheesy and simple because it is cheesy and simple,” Nichols said. “Study, study, study. Be a good test taker and a good performer. Don’t worry about what other airmen are doing. The cream is always going to rise.”

But despite the challenges, Stevens said a strategy of retraining into these in-demand careers could work for the right airmen.

“If you’re young, if you’ve decided you’re going to make a career out of the military, and you’re ambitious, heck, go for it,” Stevens said.

FAST BURNERS

An Air Force Times analysis of promotion data since 2008 shows that these are consistently the fastest-promoting career fields.

BEST BETS

Here are six of the fastest-promoting career fields, according to an Air Force Times analysis of the last six years of promotion records.

Geospatial intelligence

AFSC: 1N1X1

Re-enlistment bonus: A geospatial intelligence analyst (1N1X1A) who is a staff sergeant with seven years of service, who re-enlists for four years, would receive a bonus of about $61,600. .

Undermanned: Yes

Summary: Geospatial intelligence airmen help analyze intelligence images from satellites, remotely piloted aircraft and other sources to identify military targets and separate them from civilians.

Training: 100 to 110 days at Goodfellow Air Force Base, Texas.

Cardiopulmonary laboratory

AFSC: 4H0X1

Re-enlistment bonus: A senior airman with four years of service, who re-enlists for four years, would receive a bonus of about $18,500.

Undermanned: Yes

Summary: These airmen help doctors and other health professionals diagnose and treat diseases of the heart and lungs by performing blood tests, electrocardiograms and ultrasounds, and by assisting with catheterizations and other special studies of the heart. They also help with long-term respiratory therapy to help patients breathe, and must provide compassionate care for patients.

Training: 233 days at Fort Sam Houston, Texas.

Airborne intelligence, surveillance and reconnaissance operator

AFSC: 1A8X2

Re-enlistment bonus: A staff sergeant with six years of service, who re-enlists for four years, would receive a bonus of about $43,300.

Undermanned: Yes

Summary: Airborne ISR operators fly onboard various aircraft to gather and evaluate information on the enemy’s location, numbers, activity, and how they are supplied and supported. They must help plan missions, and then analyze and disseminate information obtained from onboard systems during those missions.

Training: 77 days at Goodfellow Air Force Base.

Airborne cryptologic language analyst

AFSC: 1A8X1

Re-enlistment bonus: A staff sergeant with five years of service, who re-enlists for four years, would receive a bonus of about $63,000.

Undermanned: Yes

Summary: Airborne cryptologists record and translate foreign communications from languages such as Farsi, Chinese, Russian, Pashtun and Korean, and then evaluate the intelligence and report on what is being said. They receive, transmit and relay encoded and decoded messages, and operate airborne signals intelligence systems and equipment.

Training: Length varies; training is usually held at Lackland Air Force Base in Texas, Goodfellow Air Force Base, or the Defense Language Institute Foreign Language Center at the Presidio of Monterey in California.

Remotely piloted aircraft sensor op

AFSC: 1U0X1

Re-enlistment bonus: A staff sergeant with five years of service, who re-enlists for four years, would receive a bonus of about $63,000.

Training: 34 days at Lackland Air Force Base or Randolph Air Force Base in Texas.

Contracting

AFSC: 6C0X1

Re-enlistment bonus: A senior airman with five years of service, who re-enlists for four years, would receive a bonus of about $47,000.

Undermanned: Yes

Summary: Contracting specialists must buy equipment, supplies and services to support their base’s activities. They decide the best way to fill purchase requests, prepare solicitation documents to receive price quotes, analyze the prices offered by prospective contractors and decide who offers the best deal for the Air Force. They also must resolve any contract problems that arise.